Polyvinyl chloride composition and sheets



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Jan..28, 1941 PATENT POLYVINYL CHLORIDE COMPOSITION 1 1 SHEETS Otto Haufle and Wilhelm Wohr, Eileh'bwig, oppassimors to Deuteche Ceiluioid-Fabrik,

'l. y, a corporation of German No Drawing. Application April is, was, Serial No. 75,241. In Germany April 20, 1935 5 Claims.

@ur present invention relates to the manufacture oi sheets from polyvinylchloride and more particularly to the manufacture of sheets from after-chlorinated polyvinylchloride.

@ne of its objects is to provide a process oi producing improved sheets from after-chlorinated polyvinylchloride. Another object is the improved sheets of after-chlorinated polyvinyl chloride. Further objects will be seen from the detailed specification following hereafter.

in making sheets, foils, films, plastic masses and the like from cellulose derivatives or synthetic highly polymeric bodies with the aid of easily volatile solvents or alone by a heat treatment, it is usual to add one or more sparingly volatile solvents, so-called softening agents, for the purpose of obtaining a material which can be rolled; While in the case of plastic masses having a cellulose derivative basis, such an addition of a softening agent does in fact lead to an improvement, not only during the rolling but also in respect of the properties of the final prodnot, in the case of synthetic highly polymeric bodies of the vinyl-group, particularly polyvinyl chloride, after-chlorinated polyvinyl chloride and mixed polymerizates of the chloride with acrylic acid derivatives, there is, indeed, a good edect experienced in the rolling operation but in respect oi the properties of the finished sheet the direct opposite is the case; thus, for example, the softening point, the mechanical strength and the dielectric properties are so far diminishedthat it is not possible to apply the sheet. Without the addition of a softening agent, however, sheets of polyvinyl chloride are too brittle and the after-chlorinated polyvinyl chloride is practical ly incapable of being rolled; there are obtained merely imeven, shriveled, fragmentary pieces which are of no use.

According to this invention it has been found that after-chlorinated polyvinyl chloride can be rolled by adding'to the material polyvinyl chloride instead of the hitherto usual softening agents. The addition of polyvinyl chloride to the afterchiorinated polyvinyl chloride may be between i and 95 per cent of the final product. Instead of polyvinylchloride there may also be used polystyrene. In this manner there are obtained without trouble, by rolling, coherent, completely smooth, not shriveled sheets of any thickness by means of thermal plastioizing. It has also been found that by rolling these materials together the mechanical properties of the polyvinyl chloride are much improved. Whereas a sheet of polyvinyl chloride of 0.12 mm. thickness shows in particular no measurable tensile strength, a sheet of similar thickness made from polyvinyl chloride and after-chlorinated polyvinyl chloride, in the proportion of 1:1, shows a tensile strength .of 6 to 7 kg. per sq. mm. and

an extension of 25 to 30 per cent in the longitudinal direction and 5 to 6 per cent. in the transverse direction. The dielectric properties of the sheet produced by rolling the polyvinyl chloride and after-chlorinatedpolyvinyl chloride 10 in the same operation are in no way afiected disadvantageously: whereas hitherto the softening point has been strongly depressed even by a small percentage addition of a softening agent,

the softening point of the after-chlorinated polyvinyl chloride is not affected by the nonchlorinated polyvinyl chloride added for the purpose of facilitating the rolling operation. An addition of, for example, per cent of phthalic acid ester to after-chlorinated polyvinyl chloride mainly for the purpose of rendering the mate.- rial capable of being rolled, produces a sheet having a softening point of about to 0., so that the sheet is quite useless for further application. If, however, the rolling of the same 25 after-chlorinated polyvinyl chloride is facilitated by addition of non-chlorinated polyvinyl chloride, for instance, in the ratio 1:1, there is obtained a sheet having a softening point of M7 to C. Besidesthe mechanical strength the sofso tening point has directly a preponderating importance in the working up of the polymeride into useful objects of any kind.

It must be regarded as a surprising advance in the art of plastic masses made from a basis 35 of synthetic polymerizates that, contrary to all expectation, by the rolling together of products which alone are not capable of being rolled or can be rolled only with great difficulty, such as after-chlorinated polyvinyl chloride, and a very o brittle polymerizate, the rolling of the product is facilitated on the one hand and on the other hand the mechanical strength of the material is improved without depressing its softening point.

What we claim is:

'1. A composition adapted to form strong, smooth, supple sheets having high insulating power and a high softening point upon hot rolling thereof in the absence of solvents, consisting of a uniform mixture of after-chlorinated polyvinyl chloride and from 10 to per cent by weight of the mixture of a vinyl polymer selected from the class consisting of polyvinyl chloride and polystyrene.

. 2. A composition as defined in claim 1, where- 55 in the said two components of the mixture are present in about equal parts by weight.

3. Smooth, strong, supple sheets of high insulating power and a. high softening point consisting of a uniform mixture of after-chlorinated polyvinyl chloride and from 10 to 95 per cent by weight of the mixture of a vinyl polymer selected from the class consisting of polyvinyl chloride and polystyrene.

4. Sheets as definedin claim 3, wherein the said two components thereof are present in about equal parts by weight.

O'I'IO HAUFFE. WILHELM WEHR. 

